Information processing apparatus and method for controlling power supply of the apparatus

ABSTRACT

The information processing apparatus includes: information processing unit configured to process various information; an interface capable of supplying electrical power to and communicating a signal with an electronic device external to the apparatus through a single connector; a power supply unit capable of supplying electrical power to the electronic device through the interface; electronic device detection unit configured to detect connection of the electronic device to the apparatus; external power supply detection unit configured to detect connection of an external power supply to the apparatus; and power supply control unit, when the connection of the electronic device and the external power supply to the apparatus are detected, configured to keep supplying electrical power to the electronic device even after deactivation of the apparatus, in the event an instruction to turn off a power supply of the apparatus or deactivate the apparatus is issued.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2004-234730, filed Aug. 11,2004, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information processing apparatus anda method for controlling a power supply of the apparatus, and moreparticularly to an information processing apparatus for supplying powerto external devices and a method for controlling a power supply of theapparatus.

2. Description of the Related Art

Nowadays, a cellular phone has been widely used in Japan as well as inall other countries around the world. The cellular phone has now digitalcamera function, Internet access function and various informationprocessing functions in addition to conventional phone function andemail function, thereby significantly increasing its convenience.Accordingly, it could be predicted that the cellular phone wouldcontinue to be widely used in the future.

Further, portable electronic devices such as digital camera, PDA(Personal Digital Assistance), portable audio player, etc., have beenalso widely used similarly to the cellular phone.

Many of these portable electronic devices incorporate a rechargeablebattery such as Lithium-ion battery and are powered by the rechargeablebattery. Further, when the rechargeable battery loses its power, thebattery is in many cases charged with electrical power from thecommercial power supply via an AC adapter, etc., dedicated to theindividual portable electronic devices.

Further, an information processing apparatus typified by a personalcomputer has also been widely used similarly to the portable electronicdevices. The information processing apparatus has various interfaces forconnection with various external devices and among these interfaces, aninterface configured in accordance with an industry standard such as theUSB (Trademark) (Universal Serial Bus) specification or the IEEE 1394specification is provided in many information processing apparatuses.

Moreover, in response to the fact that an interface designed inaccordance with the USB specification or the IEEE 1394 specificationtends to be commonly used in an information processing apparatus, manyof portable electronic devices including a cellular phone tend to beprovided with an interface designed in accordance with the USBspecification or the IEEE 1394 specification.

USB is positioned as an interface technology to be applied to a pair oflines that can carry out serial digital data transfer through abi-directional serial line as well as power and ground lines throughwhich power is supplied to external devices.

Similarly to USB, IEEE 1394 is also positioned as an interfacetechnology to be applied to a pair of lines that can carry out serialdigital data transfer and is a specification that describes a method forsupplying power to external devices.

Note that power supplied via an interface that supports the interfacespecification such as USB and IEEE 1394 is in some cases referred to asbus electrical power.

If bus electrical power can be supplied from a personal computer, etc.,through USB cables to charge the battery of a portable electronic devicesuch as a cellular phone, a user of portable electronic device is ableto enjoy great convenience because he/she has no need to bring withhimself/herself an AC adapter, etc., dedicated to individual portableelectronic devices.

Some references disclose a technique for charging the battery of aportable electronic device such as a cellular phone using bus electricalpower through USB cables.

For example, Japanese Unexamined Patent Publication (Kokai) No.2000-201204 discloses a cable having one end connected to a USBconnector of an information processing apparatus such as a personalcomputer and the other end connected to a battery charge connector on acellular phone. More specifically, the cable is for supplying buselectrical power from a USB connector provided in the informationprocessing apparatus to the cellular phone, thereby charging thecellular phone battery.

In addition to the configuration of the battery charge cable disclosedabove, Japanese Unexamined Patent Publication (Kokai) No. 2000-339067has a feature that a voltage conversion function and an over-currentprotection function are provided in the middle of the cable.

Further, Japanese Unexamined Patent Publication (Kokai) No. 2004-152317discloses a technique for efficiently utilizing capabilities enabled bythe OTG (USB On-The-Go) specification, which is a supplement to the USBspecification (USB specification version 2.0), to allow a user tofurther enjoy the convenience of charging a battery using bus electricalpower through USB cables.

In more detail, the battery charge method disclosed in above Kokai No.2000-201204 or No. 2000-339067 is to supply power in one direction only,i.e., in a direction from a host device (personal computer, etc.) to aterminal device (external device such as a cellular phone connected to apersonal computer, etc.). In other words, this method provides a“one-way” battery charge function.

In contrast to the above methods, Kokai No. 2004-152317 discloses atechnique for connecting two terminal devices (e.g., devices A and B)using a USB OTG cable and allowing a battery provided in the device A oran external power supply connected to the device A to charge the batteryof the device B. Further, the technique includes, for example, simplychanging the USB cable connection in order to allow a battery providedin the device B or an external power supply connected to the device B tocharge the battery of the device A. In this manner, the techniqueenables one of the two devices to charge the battery of the other,thereby providing a “two-way” battery charge function.

According to the battery charge techniques disclosed in abovereferences, it becomes possible to retrieve bus electrical power from aUSB connecter provided in many of nowadays information processingapparatuses and terminal devices and use the bus electrical power tocharge the battery of a portable electronic device such as a cellularphone. This eliminates the need for a user to bring out an electronicdevice such as an AC adaptor, which is dedicated to the battery chargeworking, for use at his/her destination site, thereby allowing the userof a portable electronic device to enjoy great convenience.

Note that interface specifications for USB, etc., (hereinafter, aninterface designed in accordance with the USB specification or the IEEE1394 specification to be able to supply bus electrical power arereferred to as a USB interface, etc.) are originally intended to unifyinterfaces for data communication between an information processingapparatus such as a personal computer and an external device to beconnected to the apparatus. Accordingly, in general, unless aninformation processing apparatus itself has been activated, buselectrical power is never supplied from a USB connector, etc., providedin the information processing apparatus to the external device.

A USB interface, etc., supports the “Hot Plug” function and it isassured that a USB connector, etc., is able to operate even if the USBconnector is connected via the USB interface to the informationprocessing apparatus in operation. Accordingly, as long as theinformation processing apparatus is in operation, it is possible tosupply bus electrical power to an external device and communicate datawith the external device. However, once the information processingapparatus is turned off, bus electrical power supply to the externaldevice is stopped.

For this reason, when a user tries to connect a portable electronicdevice such as a cellular phone to the information processing apparatusto charge the battery of the electronic device, the user has to keep theinformation processing apparatus turned on even if he/she is not usingthe information processing apparatus. Such an operation is notrecommended for the reduction of power consumption.

Further, keeping the information processing apparatus turned on duringoperation of a cellular phone, etc., is not recommended for the securityof the information processing apparatus and in some cases, requires thatthe user sits near the information processing apparatus until thebattery of the phone is fully charged, making the user feelinconvenient.

Further, many of nowadays information processing apparatuses, inparticular portable information processing apparatuses such as a notepersonal computer are equipped with a power saving function. The powersaving function is to automatically turn off power supplies excludingpower supplies needed for a part of electronic components of theinformation processing apparatus, for example, when a user does notoperate a key board, etc., for a predetermined period of time.

A power saving function called a “suspend” function is, for example, toautomatically turn off all of power supplies excluding a power supplyneeded for a main memory comprised of DRAM, etc., when a user does notoperate a key board, etc., for a predetermined period of time andimmediately switch back to a mode just prior to the beginning of asuspend mode based on information stored in the main memory when theuser presses any key on the keyboard.

Further, a power saving function called a “hibernation” function is tostore in an HDD (Hard Disk Drive) the information contained in a mainmemory and turn off almost all of power supplies needed for electroniccomponents including the main memory for the purpose of saving power.

The “suspend” and “hibernation” functions, etc., are very useful interms of saving power on the information processing apparatus, however,when a cellular phone, etc., is connected to the information processingapparatus for charging the battery of the phone, power supplies in theinformation processing apparatus are turned off upon automaticactivation of a power saving function before the battery is fullycharged, inconveniently interrupting the battery charge process at thispoint.

Further, it is also possible to disable the “suspend” function or“hibernation” function to preferentially charge the battery of theexternal device. However, in such a case, after completion of batterycharge, a user has to enable again those power saving functions in atime-consuming manner.

SUMMARY OF THE INVENTION

The present invention has been conceived in consideration of theabove-mentioned problems and an object of the invention is to provide aninformation processing apparatus capable of charging a battery orsupplying power to a battery of a portable electronic device, such as acellular phone, connected to the information processing apparatus, usingbus electrical power through USB cables, etc., even in a case wherepower supplies in the information processing apparatus are turned off orin a case where a power saving function in the information processingapparatus is being enabled and further to provide a method forcontrolling a power supply of the apparatus.

In a first aspect of the present invention, an information processingapparatus includes: an information processing unit configured to processvarious information; an interface capable of supplying electrical powerto and communicating a signal with an electronic device external to theapparatus through a single connector; a power supply unit capable ofsupplying electrical power to the electronic device through theinterface; an electronic device detection unit configured to detectconnection of the electronic device to the apparatus; an external powersupply detection unit configured to detect an external power supply tothe apparatus, the external power supply operable to supply electricalpower to the power supply unit; and a power supply control unit, whenthe connection of the electronic device and the external power supply tothe apparatus are detected by the electronic device detection unit andthe external power supply detection unit respectively, configured tokeep supplying electrical power to the electronic device through theinterface even after deactivation of the apparatus, in the event aninstruction to turn off a power supply of the apparatus or deactivatethe apparatus is issued.

In a second aspect of the present invention, a method for controlling apower supply of an information processing apparatus that includes aninterface capable of supplying electrical power to and communicating asignal with an electronic device external to the apparatus through asingle connector and a power supply unit capable of receiving electricalpower from an external power supply, the method includes: supplyingelectrical power to the electronic device from the power supply unitthrough the interface during operation of the information processingapparatus; and keeping supplying electrical power to the electronicdevice through the interface even after deactivation of the informationprocessing apparatus, in the event the electronic device and theexternal power supply are being connected to the information processingapparatus.

In a third aspect of the present invention, a method for controlling ofan information processing apparatus that includes an interface capableof supplying electrical power to and communicating a signal with anelectronic device external to the apparatus through a single connectorand a power supply unit having a rechargeable battery and being capableof receiving electrical power from an external power supply, the methodincludes: a first step of supplying electrical power to the electronicdevice from the power supply unit through the interface when theelectronic device is being connected to the connector during operationof the information processing apparatus; a second step of detecting thestate of the power supply unit when operation of the informationprocessing apparatus is terminated or interrupted; and a third step of,in accordance with the detected state in the second step, keepingsupplying electrical power to the electronic device through theinterface even after deactivation of the information processingapparatus.

According to the information processing apparatus and the method forcontrolling a power supply of the apparatus, even after the power supplyof the information processing apparatus is turned off or even when apower saving function of the information processing apparatus is inoperation, a portable electronic device, such as a cellular phone,coupled to the information processing apparatus can be electricallycharged or supplied with electrical charge in such a manner that buselectrical power is supplied via a USB cable, etc., to the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the first perspective view showing the appearance of—oneembodiment of an information processing apparatus according to theinvention;

FIG. 2 is the second perspective view showing the appearance of oneembodiment of an information processing apparatus according to theinvention;

FIG. 3 is a function block diagram of one embodiment of an informationprocessing apparatus according to the invention;

FIG. 4 is a system configuration diagram of one embodiment of aninformation processing apparatus according to the invention;

FIG. 5 is a detailed configuration diagram of a power supply unitaccording to one embodiment of an information processing apparatus ofthe invention;

FIG. 6 is the first flow chart for a power supply control process in oneembodiment of an information processing apparatus according to theinvention; and

FIG. 7 is the second flow chart for a power supply control process inone embodiment of an information processing apparatus according to theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of an information processing apparatus according to theinvention and a method for controlling a power supply of the apparatuswill be explained with reference to the accompanying drawings.

(1) Outline and Principle Operation of an Information ProcessingApparatus 1

FIG. 1 is a perspective view showing the appearance of one embodiment ofthe information processing apparatus 1 according to the invention.

The information processing apparatus 1 includes an informationprocessing apparatus main body 2 and a cover member 3.

The information processing apparatus main body 2 includes a thinbox-shaped main body casing 4 that accommodates electronic components,such as later described CPU 30, main memory 40 and the like, necessaryfor information processing.

On the upper surface of the main body casing 4 is provided a keyboard 9for a user to input various information. Further, on a portion of thecasing 4 closer to the user than the keyboard 9 are provided a touch pad5 for moving a pointer displayed on a display 14 integrated into thecover member 3, and a pointing device 8 comprised of a left-hand button6 used to click on or drag the pointer and a right-hand button 7.

On a portion of the casing 4 farther from the user than the keyboard 9is provided a power supply switch 10 for activating the informationprocessing apparatus 1.

The cover member 3 is capable of protecting the information processingapparatus main body 2 when the user is not using the informationprocessing apparatus 1 or is carrying the same and further is capable ofdisplaying various information, and a cover main body 13 of the covermember is attached to the main body casing 4 via two hinges 12 so as tofreely open and close.

A square opening is provided within the cover main body 13 and thedisplay 14 such as a liquid crystal display is disposed in the covermain body so that the display is exposed through the opening.

On the main body casing 4 of the information processing apparatus mainbody 2 are provided with various connectors for interfacing withexternal electronic devices. For example, an IEEE 1394 compliantconnector 11 that is designed in accordance with the IEEE 1394specification is provided on the left side face of the main body casing4 in FIG. 1.

FIG. 2 is a perspective view of the information processing apparatus 1from the backside. Also, on the back and left side faces of the mainbody casing 4 of the information processing apparatus 1 in FIG. 2 areprovided various connectors.

The information processing apparatus 1 is provided with two USBconnectors 15 compliant with USB Specification on the back side face andone USB connector 15 on the left side face in FIG. 2. Further, FIG. 2illustrates a cellular phone shown as an example of an electronic device17 external to the apparatus and connected to the apparatus via a USBcable 16.

On the back side face of the main body casing 4 is also provided a powersupply connector 18. An AC adaptor (not shown) is connected to the powersupply connector 18 and power is supplied to the information processingapparatus 1 from an external commercial power supply via the AC adaptor.

Further, on the back side face of the main body casing 4 is provided aconnector door 19. Inside the connector door 19 are provided a RGBconnector 19 a used to display images, for example, on an external CRTand a LAN (Local Area Network) connector 19 b for interfacing with anelectrical communication line such as the Internet.

Note that the information processing apparatus 1 according to theinvention is not limited to the structure having appearance, shape,size, etc., shown in FIGS. 1 and 2. For example, the informationprocessing apparatus 1 shown in FIGS. 1 and 2 has the appearance of aso-called note personal computer, however, it may be a stationary-typedisk-top personal computer. Further, the information processingapparatus 1 may be configured to have the display 14 and the informationprocessing apparatus main body 2 disposed separately from each other.Additionally, the information processing apparatus 1 could be, forexample, a server, etc., without the display 14.

FIG. 3 is a function block diagram illustrating main functions availablein the information processing apparatus 1.

The information processing apparatus 1 includes information processingunit 21 for processing of various information as well as external powersupply detection unit 23 for detecting connection of an external powersupply 22 and electronic device detection unit 24 for detectingconnection of an external electronic device 17 such as a cellular phone.

Further, the information processing apparatus 1 includes: a power supplyunit 25 for converting voltages supplied from the external power supply22 to voltages adjusted to individual electronic components included inthe information processing apparatus 1 and delivering/supplying theadjusted voltages to the individual electronic components; and powersupply control unit 26 for performing various control on the powersupply unit 25.

Moreover, the information processing apparatus 1 includes an interface27 for communication of various signals between the informationprocessing unit 21 and the external electronic device 17 and supplyingpower called bus electrical power to the external electronic device 17.

The interface 27 includes a USB compliant connector, etc., as well as aUSB controller, etc. The USB controller, etc., is for convertingparallel data to serial data to produce a USB bus signal, etc., andcontrolling bus electrical power.

Additionally, the information processing apparatus 1 may be configuredto include type determination unit 28 for determining the type of theexternal electronic device 17 based on a signal received through theinterface 27 and power saving unit 29 for reducing power consumption ofthe information processing apparatus 1 in accordance with apredetermined procedure.

With reference to FIG. 3, the principle operation of the informationprocessing apparatus 1, in particular the basic operation of how theapparatus controls power supply will be explained.

The power supply unit 25 of the information processing apparatus 1receives power from the external power supply 22. The external powersupply 22 could be, for example, a DC power supply that will provide aDC voltage which is produced when a voltage from a commercial powersupply (100V, 50/60 Hz) is converted by the AC adaptor, etc. Inaddition, the apparatus may be configured to supply an AC voltage fromthe commercial power supply directly to the power supply unit 25 wherethe AC voltage is converted to the DC voltage.

The power supply unit 25 may be configured to include a rechargeablebattery 251, e.g., lithium-ion battery or nickel-hydrogen battery. In acase where the power supply unit 25 incorporates the rechargeablebattery 251, when the external power supply 22 is not connected to theapparatus, the electrical power of the battery 251 is supplied to theindividual electronic components of the information processing apparatus1. On the other hand, when the external power supply is connected to theapparatus, the electrical power of the external power supply 22 ispreferentially supplied to the individual electronic components of theinformation processing apparatus 1. Further, when the electrical powerof the battery 251 is insufficient, the battery 251 is charged by theexternal power supply 22.

The power supply unit 25 converts the electrical power from the externalpower supply 22 or the battery 251 to voltages, e.g., 5V or 3.3Vadjusted to the individual electronic components of the informationprocessing apparatus 1, and then delivers the voltages to the individualelectronic components. The voltages are delivered to the individualelectronic components, respectively, or via a power delivery switch 255(refer to FIG. 5) capable of turning on and off the corresponding powersupply for each of individual groups formed by dividing a plurality ofelectronic components into a plurality of groups.

The power supply unit 25 is controlled by the power supply control unit26.

There are various methods for activating the information processingapparatus 1. The most general method is to allow a user to press thepower supply switch 10 (refer to FIG. 1) of the information processingapparatus main body 2 to activate the information processing apparatus1.

More specifically, the power supply control unit 26 recognizes, as anactivation instruction signal, a signal from the power supply switchpressed by the user and transmits a control signal to the power supplyunit 25. The power supply unit 25 receives the control signal and turnson the power delivery switch to deliver electrical power to theindividual electronic components of the information processing apparatus1.

Further, the apparatus may be, for example, configured to generate anactivation instruction signal at predetermined time points or togenerate an activation instruction signal in response to an instructionfrom outside via a telecommunication line, in order to activate theinformation processing apparatus 1.

When electrical power is supplied to the individual electroniccomponents of the information processing apparatus 1, for example, theBIOS (Basic Input/Output System) is read out from a non-volatile memorycalled a BIOS-ROM and an OS (Operating System) stored, for example, inan HDD (Hard Disk Drive) is subsequently activated.

After activation of the OS, various application software such asdocument creation and spreadsheet software are activated to performvarious information processing tasks.

Note that the information processing unit 21 of FIG. 3 operates as apart of the BIOS and OS or executes various application softwares forprocessing of information.

Upon activation of the OS, signals can be communicated between theinformation processing apparatus 1 and the external electronic device 17connected to the apparatus via the interface 27.

Although the information processing apparatus 1 may include variousinterfaces, it includes at least the USB interface 27 that includes asingle connector for allowing communication of signals and supply ofelectrical power, as shown in FIG. 3.

The electronic device detection unit 24 is capable of detecting that theexternal electronic device 17 is being connected to the apparatus viathe USB interface 27 and the information processing unit 21. Theinformation processing unit 21 and the external electronic device 17communicate signals to each other via a serial bus of the USB, etc., andthe signal communicated therebetween allows for detection of connectionof the external electronic device 17.

The signals communicated via the serial buses also include informationindicating the type of the external electronic device 17. The typedetermination unit 28 is for determining the type of the externalelectronic device 17 based on the information indicative of the type andclassifying the device. More specifically, when the external electronicdevice 17 is, for example, a portable electronic device, such as acellular phone, incorporating a rechargeable battery, the device 17 isclassified into a category “A”. Further, when the external electronicdevice 17 is, for example, an electronic device that includesnon-portable electronic components, such as a mouse and a scanner, whichshould be used while being coupled to the information processingapparatus 1 and which are operated only by bus electrical power suppliedthrough the USB compliant interface 27, or an electronic device thatdoes not use bus electrical power, the device 17 is classified into acategory “B”.

When the electronic device 17 classified into the category “A” isconnected to the USB compliant interface 27, bus electrical power issupplied via the interface 27. A battery incorporated within theelectronic device 17 classified into the category “A” is charged withthe bus electrical power. At least during operation of the informationprocessing apparatus 1, the battery charge is continued. Note that ingeneral, it is also possible to operate the electronic device 17 usingthe bus electrical power while charging the battery, however, whether ornot it is possible to operate the device in such a manner depends onwhat the electronic device 17 connected to the apparatus is.

The USB compliant interface 27 is provided with a so-called hot plugfunction. Accordingly, even when the external electronic device 17 isconnected to the interface 27 after activation of the OS, the apparatus1 is able to detect presence/absence of connection, type and category ofthe electronic device 17.

The electronic device detection unit 24 and the type determination unit28 store a flag indicative of presence/absence of connection of theelectronic device 17 and the category of the electronic device 17 in anappropriate memory.

The external power supply detection unit 23 is for detectingpresence/absence of connection of the external power supply 22.Detection of presence/absence of connection of the external power supply22 is possible, for example, by comparison between a power supplyvoltage supplied from the external power supply 22 and a predeterminedthreshold value. The external power supply detection unit 23 stores inan appropriate memory a flag indicative of presence of connection of theexternal power supply 22 upon detection of connection of the externalpower supply 22.

There are various ways for a user to deactivate (turn off) theinformation processing apparatus 1. For example, the user often takesthe step of opening a shutdown window during activation of OS andclicking on a display of “Shut Down” to cause the apparatus to bedeactivated (deactivation instruction). Clicking on the display to causethe apparatus to be deactivated allows a predetermined shutdownprocedure to take place, e.g., allows data needed under control by theOS to be stored in the HDD.

The deactivation instruction is transmitted to the power supply controlunit 26. The power supply control unit 26 supplies a control signal tothe power supply unit 25 in order to stop the supply of electrical powerto the individual electronic components of the information processingapparatus 1.

In response to the control signal, the power supply unit 25 turns off apower distribution switch used to supply electrical power to theindividual electronic components. The power distribution switch 255 iscapable of being turned off for each of the individual electroniccomponents or for each of groups of the electronic components.

Conventionally, irrespective of presence/absence of connection of theexternal electronic device 17, the supply of electrical power to nearlyall of the electronic components excluding small power consumptionelectronic components such as a keyboard controller 80 (refer to FIG. 4)is stopped. As a result, the supply of bus electrical power from theinterface 27 is also stopped.

Accordingly, there has been a problem that even in a case where theapparatus has the external electronic device 17 connected thereto andthe battery charge to the device 17 has not been completed, the batterycharge is interrupted during supply of electrical charge.

In contrast to it, the information processing apparatus 1 according tothe invention is configured so that the electronic device detection unit24 stores information indicative of presence/absence of connection ofthe external electronic device 17 in a flag. The power supply controlunit 26 checks the flag after receipt of the deactivation instructionand when the external electronic device 17 is being connected to theapparatus, instructs the power supply unit 25 to keep supplying buselectrical power to the external electronic device 17 while stopping thesupply of electrical power to the electronic components other than thosenecessary for the supply of electrical power to the external electronicdevice 17.

More specifically, for example, switches on the power distributionswitch 255 are controlled so that the supply of electrical power to theUSB controller 70 (refer to FIG. 4) constituting the interface 27 iscontinued while the supply of electrical power to the electroniccomponents other than the USB controller 70 is stopped.

In a case where the external electronic device 17 is being connected tothe apparatus, such a power supply control procedure in the informationprocessing apparatus 1 allows the apparatus to keep supplying buselectrical power to the electronic device 17 even when the informationprocessing apparatus 1 is deactivated and prevents the problem of havingthe battery charge stopped during supply of electrical charge to thebattery of the external electronic device 17.

The electronic device 17 to be connected to the information processingapparatus 1 also includes the electronic device classified into thecategory “B”. The electronic device 17 classified into the category “B”is a mouse or scanner that does not need to be electrically charged andnever be adversely affected even when bus electrical power beingsupplied to the device 17 is stopped immediately when the informationprocessing apparatus 1 is deactivated.

When all of the electronic devices 17 being connected to the informationprocessing apparatus 1 are classified into the category “B”, no benefitresults from keeping supplying bus electrical power through theinterface 27 even after deactivation of the information processingapparatus 1. Keeping supplying bus electrical power through theinterface 27 even after deactivation of the information processingapparatus 1 means that unnecessary electrical power is supplied to theUSB controller 70 used in the interface 27, causing an adverse effect onthe apparatus.

To prevent such unnecessary electrical power consumption, the type ofthe electronic device 17 being connected to the apparatus is determinedby the type determination unit 28 and even when the electronic devices17 are being connected to the apparatus and further when all of theelectronic devices 17 belong to the category “B”, it is preferred thatthe supply of electrical power to the USB controller 70 is stoppedimmediately when the information processing apparatus 1 is deactivated,in order to stop supply of bus electrical power.

Consequently, unnecessary electrical power is not dissipated andelectrical power of the information processing apparatus 1 can be saved.

Further, in the embodiment, keeping supplying bus electrical power evenafter deactivation of the information processing apparatus 1 requiresinformation indicative of connection of the external power supply 22 inaddition to information indicative of presence/absence of connection ofthe electronic device 17.

As a result, even when the information processing apparatus 1 is beingoperated only by the battery 251 incorporated within the apparatus,problematic situation in which continued supply of bus electrical powerto the external electronic device 17 even after deactivation of theinformation processing apparatus potentially causes the drainage orover-discharge of the battery 251 can be avoided.

Note that presence/absence of connection of the external power supply 22is detected by the external power supply detection unit 23.

Further, the apparatus may be configured so that when the absence ofconnection of the external power supply 22 is detected by the externalpower supply detection unit 23, the supply of bus electrical power tothe external electronic device 17 is stopped even during operation ofthe information processing apparatus 1. Stopping of the supply of buselectrical power contributes to reduction of electrical power consumedby the battery 251.

Note that many of nowadays information processing apparatuses,particularly portable information processing devices such as a notepersonal computer, are provided with a power saving function such as a“suspend” or “hibernation” function. The power saving function such as a“suspend” or “hibernation” function is very useful in terms of reductionof electrical power consumed by the information processing apparatus 1.However, in a case where the external electronic device 17 such as acellular phone is connected to the information processing apparatus 1 inorder to charge the battery of the device, when such a power savingfunction is automatically activated before the battery is fully charged,the power supply of the information processing apparatus 1 is turned offaccordingly and at that instant, the battery charge is stopped, causinginconvenience to a user.

Further, it is also possible to disable the “suspend” or “hibernation”function to preferentially charge the battery of the external device.However, in such a case, after the battery is fully charged, a user hasto operate to enable again those power saving functions in atime-consuming manner.

Accordingly, in a case where the information processing apparatus 1 hasprovided therein power saving unit 29 for implementing those powersaving functions, the apparatus is configured so that a power supplycontrol instruction to be outputted to the power supply control unit 26from the power saving unit 29 for power saving is issued in the samemanner as the instruction to deactivate the apparatus.

Consequently, even if supply of electrical power to substantially all ofthe electronic components of the information processing apparatus 1 isstopped when the power saving function such as “suspend” or“hibernation” function is activated, the supply of bus electrical powervia the interface 27 can be maintained to keep supplying electricalcharge to the battery of the electronic device 17 such as a cellularphone even during a power saving mode.

(2) Detailed Configuration of Information Processing Apparatus 1

FIG. 4 is the exemplary configuration of the information processingapparatus 1, showing main electric components (hardware) provided in theapparatus. The individual functional unit shown in FIG. 3 can beimplemented by causing a CPU to execute predetermined software.

As shown in FIG. 4, the information processing apparatus 1 includes aCPU 30 for executing various software, a main memory 40 for temporarilystoring software executed by the CPU 30 and data, an HDD 50 for storingsoftware and data in a non-volatile storage medium, and a graphiccontroller 60 for controlling display of various information and imagesto be displayed on a display 14, in which all of these individualelectronic components are connected to an internal bus 90.

Also, the information processing apparatus 1 further includes a USBcontroller 70 for effecting conversion between data on the internal busand serial USB signals while generating a bus electrical power controlsignal, and a power supply unit 25 for supplying electrical power to theUSB controller 70 and the other electronic components while supplyingbus electrical power via the USB connector 15. Both the USB controller70 and the power supply unit 25 are connected to the internal bus 90.

In addition to the above electronic components, the apparatus includes akeyboard controller 80 for converting signals from a power supply switch10, keyboard 9 and pointing device 8, and coupling the signals to theinternal bus 90.

To the information processing apparatus 1 is coupled an electronicdevice A17 a and an electronic device B17 b via the USB connectors 15.The electronic device A17 a is an electronic device classified into thecategory “A”, for example, a portable electronic device such as acellular phone and incorporates a rechargeable battery. On the otherhand, the electronic device B17 b is an electronic device classifiedinto the category “B”, for example, a mouse that does not incorporate abattery.

Although the embodiment of the information processing apparatus 1 ofFIG. 4 is shown as having two USB connectors 15, the number of the USBconnectors 15 is not limited to two, but may be one or not less thanthree. Further, instead of employing the USB interfaces (USB controller70 and USB connectors 15), the apparatus could employ IEEE 1394interfaces (IEEE 1394 controller and IEEE 1394 connectors: not shown).Moreover, the apparatus may include both the USB interfaces and IEEE1394 interfaces. Alternatively, the apparatus could employ Power overEthernet products certified compliant with IEEE 802.3af standard.

Further, one possible embodiment of the invention is to allow theinterface provided in the information processing apparatus 1 to transmitsignals and bus electrical power through a single connector.

FIG. 5 is a diagram illustrating the detailed configuration of the powersupply unit 25.

The power supply unit 25 includes a rechargeable battery 251.Additionally, the power supply unit 25 includes a voltage detectioncircuit 252 for detecting presence/absence of connection of an externalpower supply and a charge switch circuit 253 for switching a connectionfrom the external power supply 22 to the battery 251 and vice versa inresponse to information indicative of presence/absence of connection ofthe external power supply 22 and allowing the external power supply 22to charge the battery 251 with electrical power.

The power supply unit 25 further includes a power supply controller 254.The power supply controller 254 is connected to the internal bus 90 andoperable to receive a power supply control signal for control of thepower supply unit 25 and to output power supply information indicativeof presence/absence of connection of the external power supply 22 to theinternal bus 90.

Moreover, the power supply unit 25 further includes a power distributionswitch 255 for switching between supply and cutoff of the supply ofelectrical power to the USB controller 70 and the remaining electroniccomponents in response to the control signal from the power supplycontroller 254, and a bus electrical power switch 256 for switchingbetween supply and cutoff of the supply of bus electrical power throughUSB interfaces in response to the control signal from the USB controller70.

(3) Detailed Description of how Information Processing Apparatus 1Controls Power Supply.

With reference to FIGS. 4 and 5, how the information processingapparatus 1 controls power supply will be explained below.

In a case where the external power supply 22 is being connected to theinformation processing apparatus 1, electrical power from the externalpower supply 22 is supplied through the charge switch circuit 253 of thepower supply unit 25 to charge the battery 251, as shown in FIG. 5. Inthis case, if the overcharging prevention function, etc., provided inthe charge switch circuit 253 is activated automatically when thebattery 251 is fully charged, no charging is applied to the battery 251.

The presence/absence of connection of the external power supply 22 isdetermined by, for example, whether or not a voltage detected by thevoltage detection circuit 252 is beyond a predetermined threshold value.When the presence of connection of the external power supply 22 isdetected, the charge switch circuit 253 switches a connection from thebattery 251 to the external power supply 22 in order to preferentiallyoutput the electrical power from the external power supply 22.

On the other hand, in a case where the external power supply 22 is notconnected to the apparatus, the electrical power from the battery 251 isoutput through the charge switch circuit 253.

The electrical power output from the charge switch circuit 253 issupplied to the power distribution switch 255, bus electrical powerswitch 256, power supply controller 254, and keyboard controller 80 ofthe power supply unit 25, irrespective of whether the informationprocessing apparatus 1 is in operation or out of operation.

While the information processing apparatus 1 is out of operation (thepower supply is turned off), a user presses the power supply switch 10and then a signal generated by pressing of the switch is transmitted viathe keyboard controller 80 to the power supply controller 254 of thepower supply unit 25.

The power supply controller 254 recognizes the signal generated bypressing of the power supply switch 10 as an instruction signal foractivating the information processing apparatus 1 and instructs thepower distribution switch 255 to make proper connections so that all ofthe switches are closed to supply electrical power to the individualelectronic components of the information processing apparatus 1.

When the electrical power is supplied to the individual electroniccomponents of the information processing apparatus 1, first, BIOSstored, for example, in the non-volatile memory (not shown) is activatedand then OS 503 stored in the HDD 50 is activated.

Upon the activation of the OS 503, for example, an appropriateinstruction from a user allows various kinds of application software 501to be activated.

The OS 503 includes software modules for control of power supply, suchas a power supply control module 504, external power supply detectionmodule 505, electronic device detection module 506, and typedetermination module 507.

The power supply control module 504 is operable to control supply ofelectrical power to the individual electronic components of theinformation processing apparatus 1 and supply of bus electrical powerthrough the USB connector 15.

The external power supply detection module 505 is operable to monitorpresence/absence of connection of the external power supply 22 based oninformation from the voltage detection circuit 252 of the power supplyunit 25 and store in an appropriate memory a flag indicative of thepresence/absence of connection of the external power supply 22 when theexternal power supply 25 is provided, external to the apparatus, formaking connection to the apparatus.

The electronic device detection module 506 is operable to monitorpresence/absence of connection of the external electronic device 17based on information from the USB controller 70 and store in anappropriate memory a flag indicative of the presence/absence ofconnection of the external electronic device when the electronic device17 is provided, external to the apparatus, for making connection to theapparatus.

Further, the type determination module 507 is operable to determine thetype of the electronic device 17 connected to the apparatus based oninformation from the USB controller 70 and identify whether theelectronic device 17 is the electronic device 17 a belonging to thecategory “A” or the electronic device 17 b belonging to the category“B”, and then, store a flag indicative of the category or type in anappropriate memory.

During operation of the information processing apparatus 1, electricalpower is also being supplied to the USB controller 70. The USBcontroller 70 performs conversion between a signal on the internal bus90 and a USB signal (i.e., communication signal between the externalelectronic device 17 connected via the USB connector 15 and theapparatus 1). Further, the USB controller controls the supply and cutoffof bus electrical power supplied to the external electronic device 17from the USB connector 15.

For example, the USB controller 70 controls the supply of bus electricalpower so that all bus electrical power in an initial operational stateis supplied to the corresponding electronic components. This control isperformed by transmitting a control signal (bus electrical power controlsignals A, B) from the USB controller 70 to the bus electrical powerswitch 256 of the power supply unit 25 (refer to FIG. 5). The buselectrical power switch 256 is operable to convert electrical power fromthe external power supply 22 or the battery 251 to a predeterminedvoltage, e.g., 5 volts, and then supply as bus electrical powers A, Bthe voltages via the switches that are turned on/off in response to thebus electrical power control signals A, B to the individual USBconnectors 15. In the initial operational state (i.e., the stateresulting from activation of the information processing apparatus 1 thathas been out of operation), bus electrical power is supplied to both theexternal electronic devices A17 a and B17 b.

During operation of the information processing apparatus 1, theindividual software modules, placed in the OS, such as the power supplycontrol module 504, external power supply detection module 505,electronic device detection module 506, and type determination module507 are always operating (or operate at certain time intervals).

Accordingly, even in a case where the external power supply 22 isdisconnected from the apparatus, or the type of the electronic deviceA17 a or B17 b is altered or the electronic device A17 a or B17 b isdisconnected from the apparatus during operation of the informationprocessing apparatus 1, the apparatus is able to detect a change in theoperational state of the apparatus. Consequently, a flag indicative ofpresence/absence of connection of the external power supply 22,presence/absence of connection of the external electronic device 17, orthe type of the electronic device 17 is always updated to reflect thelatest state of the apparatus by operation of the external power supplydetection module 505, electronic device detection module 506, and typedetermination module 507.

During operation of the information processing apparatus 1, the powersupply control module 504 typically performs control so that buselectrical power is supplied via the USB connector 15.

Note that in a case where the external power supply is not connected tothe apparatus, the embodiment of the apparatus may be configured toperform control so that the supply of bus electrical power is stoppedeven during operation of the information processing apparatus 1. This isbecause there sometimes is a need to give the information processingwithin the information processing apparatus 1 priority over the supplyof bus electrical power to the external electronic device 17, dependingon the power capacity of the battery provided in the informationprocessing apparatus 1.

If the information processing apparatus 1 is deactivated or adeactivation instruction is issued to the apparatus when the suspendfunction, etc., is activated, the power supply control module 504 placedin the OS 503 checks a flag indicative of presence/absence of connectionof the external power supply 22, presence/absence of connection of theexternal electronic device 17, or the type of the electronic device 17.

When the fact that the external power supply 22 is being connected tothe apparatus and the electronic device 17 external to the apparatus isbeing connected to the apparatus is found as a result of checking of theflag, the power supply control module 504 instructs the power supplycontroller 254 of the power supply unit 25 to keep supplying electricalpower to the USB controller 70 even in the event the informationprocessing apparatus 1 is deactivated. Simultaneously, the power supplycontroller 254 instructs the USB controller 70 to keep supplying buselectrical power even in the event the information processing apparatus1 is deactivated.

Upon receipt of the instruction to keep supplying bus electrical power,the USB controller 70 sets bus electrical power control signals A, B sothat the bus electrical power switch 256 continues to be turned on evenafter deactivation of the information processing apparatus 1. In thiscase, the apparatus may perform control so that the USB controller 70checks the type of the electronic device 17 connected to the apparatusand when the electronic device 17 belongs to the category “A”, instructsthe bus electrical power switch 256 to keep supplying electrical powerto the corresponding electronic device 17 a, and when the electronicdevice 17 belongs to the category “B”, instructs the switch 256 to stopsupplying electrical power to the corresponding electronic device 17 b.

It should be noted that when the deactivation instruction is issued inresponse to deactivation of the apparatus (turning off of the powersupply of the information processing apparatus 1), the power supplycontrol module 504 may stop supply of electrical power to the electroniccomponents other than the USB controller 70, as shown in the switchingdiagram of the power distribution switch 255 in FIG. 5.

By contrast, if the deactivation instruction is issued when the powersaving function such as suspend function is activated, the power supplycontrol module 504 may keep supplying electrical power to thepredetermined electronic components, e.g., the main memory 40, inaddition to the USB controller 70 and stop supply of electrical power tothe electronic components other than those predetermined electroniccomponents.

FIGS. 6 and 7 are a flow chart showing how the information processingapparatus 1 controls the power supply.

FIG. 6 is a flow chart showing a process ranging from theout-of-operation (step ST10) of the information processing apparatus 1to the in-operation thereof. Further, FIG. 7 is a flow chart showing aprocess ranging from the in-operation of the apparatus to theout-of-operation thereof (step ST26) upon receipt of deactivationinstruction by the apparatus.

In step ST11 of FIG. 6, the information processing apparatus 1 monitorspresence/absence of activation instruction. In the informationprocessing apparatus 1, even during the out-of-operation period,electrical power is continually supplied to the keyboard controller 80,power supply controller 254, etc., and thus those electronic componentsare operating. When a user presses, for example, the power supply switch10, the apparatus recognizes the signal from the switch as an activationinstruction.

In step ST12, the power supply unit 25 turns on power supply switchescorresponding to the individual electronic components. Afterwards, theOS 503 is activated. After activation of the OS 503, the informationprocessing apparatus 1 operates in operation mode.

During operation of the information processing apparatus 1, theelectronic device detection module 506 placed in the OS 503 ismonitoring presence/absence of connection of the external electronicdevice 17 (step ST13). In this case, the apparatus may be configured sothat the type determination module 507 placed in the OS 503 monitors thetype of the external electronic device 17 as well and determines whetherthe electronic device connected to the apparatus is a predefinedelectronic device belonging to the category “A” or an electronic devicebelonging to the category “B”, i.e., an electronic device other than thepredefined electronic device.

When the predefined electronic device 17 is being connected to theapparatus, an appropriate flag indicating “presence of connection of USBdevice” is stored in an appropriate memory (step ST14) By contrast, thepredefined electronic device 17 is not connected to the apparatus, theflag indicating “presence of connection of USB device” is reset (stepST15).

Further, the external power supply detection module 505 placed in the OS503 monitors whether or not the external power supply 22 is beingconnected to the apparatus (step ST16). When the external power supply22 is being connected to the apparatus, an appropriate flag indicating“presence of connection of external power supply” is stored in anappropriate memory (step ST17). By contrast, the external power supply22 is not connected to the apparatus, the flag indicating “presence ofconnection of external power supply” is reset (step ST18).

Afterwards, the information processing apparatus 1 performs variousinformation processing tasks (step ST19). Note that the process rangingfrom step ST13 to step ST18 may be performed by temporarily interruptingthe execution of the various information processing tasks (step ST19).

During operation of the information processing apparatus 1,presence/absence of deactivation instruction is being monitored (stepST20 of FIG. 7).

In response to detection of the presence of deactivation instruction(yes at step ST 20), the power supply control module 504 placed in theOS 503 checks the flag indicating “presence of connection of USBdevice”. When the flag indicating “presence of connection of USB device”is being set up, the power supply control module 504 further checks theflag indicating “presence of connection of external power supply”.

When the flag indicating “presence of connection of external powersupply” is being set up (yes at step ST 22), i.e., both the flagindicating “presence of connection of USB device” and the flagindicating “presence of connection of external power supply” are beingset up, the apparatus instructs the USB controller 70 to “keep supply”of bus electrical power to the predetermined USB device (electronicdevice 17 a) (step ST23). Further, the apparatus instructs the powersupply controller 254 of the power supply unit 25 to “keep supply” ofelectrical power to the USB controller 70 (step ST24).

Afterwards, the supply of electrical power to the electronic componentscorresponding to the instruction to “keep supply” of electrical powerand the supply of bus electrical power to the electronic componentscorresponding to the instruction to “keep supply” of bus electricalpower are maintained and supply of electrical power to the remainingelectronic components is stopped, thereby causing the apparatus to beout of operation (steps ST25 and ST26).

It should be appreciated that when any one of the flag indicating“presence of connection of USB device” and the flag indicating “presenceof connection of external power supply” is not being set up (no at stepST 21 and no at step ST 22), no electronic component is instructed to“keep supply” of electrical power and thus all supplies of buselectrical power are stopped and the supply of electrical power to theUSB controller 70 is also stopped, thereby causing the apparatus to beout of operation (step ST26).

It should be understood that the invention is not limited solely to theabove embodiments, but it is apparent that in practice, variousmodifications can be made to the components without departing the spiritand scope of the invention. Further, the use of an appropriatecombination of a plurality of the components disclosed in the aboveembodiments would permit a skilled person to develop various inventions.For example, some components may be excluded from all of the componentsdescribed in the embodiments. Further, the components used in thedifferent embodiments may be appropriately combined.

For example, in the above embodiments, in order to keep supplying buselectrical power to the external electronic device 17 in the event theinformation processing apparatus 1 is deactivated, two conditions haveto be confirmed, i.e., presence/absence of connection of the electronicdevice 17 and presence/absence of connection of the external powersupply 22 have to be checked.

By contrast, rather than determining only the presence/absence ofconnection of the external power supply 22, another embodiment involvesdetermining the state of a power supply group consisting of the powersupply unit 25 and the external power supply 22, i.e., determining thestate of the power supply unit 25 and the presence/absence of connectionof the external power supply 22. In this case, in order to keepsupplying bus electrical power to the external electronic device 17, thepresence/absence of connection of the electronic device 17 and the stateof the power supply unit 25 have to be determined.

The state of the power supply unit 25 includes the presence/absence ofconnection of external power supply 22 as well as the remaining capacityof the battery 251 provided in the power supply unit 25. For example,the apparatus may be configured so that the charge switch circuit 253detects the remaining capacity of the battery 251 and when the remainingcapacity is not less than a predetermined threshold value, for example,70% of rated capacity, the apparatus keeps supplying bus electricalpower even in a case where the external power supply 22 is not connectedto the apparatus and when the remaining capacity is less than 70% ofrated capacity, the apparatus stops supply of bus electrical powerunless the external power supply 22 is being connected to the apparatus.In such an embodiment of the apparatus, whether the supply of buselectrical power is to be maintained can be determined based on theoverall state of the power supply unit 25 that includes the externalpower supply 22 and battery 251 and therefore an opportunity for theapparatus to be able to charge the battery of the external electronicdevice 17 increases, allowing the apparatus to provide even greaterconvenience to a user.

1. An information processing apparatus comprising: an informationprocessing unit configured to process various information; an interfacecapable of supplying electrical power to and communicating a signal withan electronic device external to the apparatus through a singleconnector; a power supply unit capable of supplying electrical power tothe electronic device through the interface; an electronic devicedetection unit configured to detect connection of the electronic deviceto the apparatus; an external power supply detection unit configured todetect an external power supply to the apparatus, the external powersupply operable to supply electrical power to the power supply unit; anda power supply control unit, when the connection of the electronicdevice and the external power supply to the apparatus are detected bythe electronic device detection unit and the external power supplydetection unit respectively, configured to keep supplying electricalpower to the electronic device through the interface even afterdeactivation of the apparatus, in the event an instruction to turn off apower supply of the apparatus or deactivate the apparatus is issued. 2.The information processing apparatus according to claim 1, wherein thepower supply unit includes a rechargeable battery and the power supplycontrol unit does not supply electrical power to the electronic devicethrough the interface even during operation of the apparatus in theevent the external power supply for charging the battery is not beingconnected to the apparatus.
 3. The information processing apparatusaccording to claim 1, further comprising a predetermined power savingunit, wherein the power supply control unit keeps supplying electricalpower to the electronic device even after the apparatus is deactivatedby the power saving unit.
 4. The information processing apparatusaccording to claim 1, further comprising a type determination unitconfigured to determine a type of the electronic device connected to theapparatus, wherein in the event the type determined by the typedetermination unit is a predetermined type, the power supply controlunit keeps supplying electrical power to the electronic device of thepredetermined type even after deactivation of the apparatus and whereinin the event the determined type is different from the predeterminedtype, the power supply control unit stops supply of electrical power toan electronic device whose type is different from the predetermined typeafter deactivation of the apparatus.
 5. The information processingapparatus according to claim 4, wherein the electronic device of thepredetermined type is a portable electronic device incorporating arechargeable battery.
 6. The information processing apparatus accordingto claim 1, wherein the interface is any one of a USB (Universal SerialBus) compliant interface, IEEE-1394 compliant interface, and IEEE802.3af-compliant Power-over-Ethernet (trademark).
 7. A method forcontrolling a power supply of an information processing apparatus thatincludes an interface capable of supplying electrical power to andcommunicating a signal with an electronic device external to theapparatus through a single connector and a power supply unit capable ofreceiving electrical power from an external power supply, the methodcomprising: supplying electrical power to the electronic device from thepower supply unit through the interface during operation of theinformation processing apparatus; and keeping supplying electrical powerto the electronic device through the interface even after deactivationof the information processing apparatus, in the event the electronicdevice and the external power supply are being connected to theinformation processing apparatus.
 8. The method for controlling a powersupply of an information processing apparatus according to claim 7,wherein the power supply unit includes a rechargeable battery andwherein electrical power is not supplied to the electronic devicethrough the interface even during operation of the informationprocessing apparatus in the event the external power supply for chargingthe battery is not connected to the apparatus.
 9. The method forcontrolling a power supply of an information processing apparatusaccording to claim 7, wherein the information processing apparatusfurther includes predetermined power saving unit and wherein the supplyof electrical power to the electronic device is continued even after theapparatus is deactivated by the power saving unit.
 10. The method forcontrolling a power supply of an information processing apparatusaccording to claim 7, further comprising: determining a type of theelectronic device connected to the apparatus; keeping supplyingelectrical power to the electronic device of the predetermined type evenafter deactivation of the apparatus in the event the type of theelectronic device is a predetermined type; and stopping supply ofelectrical power to the electronic device whose type is different fromthe predetermined type after deactivation of the apparatus.
 11. Themethod for controlling a power supply of an information processingapparatus according to claim 10, wherein the electronic device of thepredetermined type is a portable electronic device incorporating arechargeable battery.
 12. The method for controlling a power supply ofan information processing apparatus according to claim 7, wherein theinterface is any one of a USB (Universal Serial Bus) compliantinterface, IEEE-1394 compliant interface, IEEE802. 3af-compliantPower-over-Ethernet (trademark).
 13. A method for controlling of aninformation processing apparatus that includes an interface capable ofsupplying electrical power to and communicating a signal with anelectronic device external to the apparatus through a single connectorand a power supply unit having a rechargeable battery and being capableof receiving electrical power from an external power supply, the methodcomprising: a first step of supplying electrical power to the electronicdevice from the power supply unit through the interface when theelectronic device is being connected to the connector during operationof the information processing apparatus; a second step of detecting thestate of the power supply unit when operation of the informationprocessing apparatus is terminated or interrupted; and a third step of,in accordance with the detected state in the second step, keepingsupplying electrical power to the electronic device through theinterface even after deactivation of the information processingapparatus.
 14. The method for controlling of an information processingapparatus according to claim 13, wherein the third step is performedwhen one of the two facts that the power supply unit is receivingelectrical power from the external power supply and that the remainingcapacity of the battery of the power supply unit is not less than apredetermined threshold value is detected in the second step.